1 /*-
2 * Copyright (c) 1982, 1986, 1988, 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)ip_output.c 8.3 (Berkeley) 1/21/94
30 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34
35 #include "opt_ipfw.h"
36 #include "opt_ipsec.h"
37 #include "opt_mac.h"
38 #include "opt_mbuf_stress_test.h"
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/malloc.h>
44 #include <sys/mbuf.h>
45 #include <sys/priv.h>
46 #include <sys/protosw.h>
47 #include <sys/socket.h>
48 #include <sys/socketvar.h>
49 #include <sys/sysctl.h>
50
51 #include <net/if.h>
52 #include <net/netisr.h>
53 #include <net/pfil.h>
54 #include <net/route.h>
55
56 #include <netinet/in.h>
57 #include <netinet/in_systm.h>
58 #include <netinet/ip.h>
59 #include <netinet/in_pcb.h>
60 #include <netinet/in_var.h>
61 #include <netinet/ip_var.h>
62 #include <netinet/ip_options.h>
63
64 #ifdef IPSEC
65 #include <netinet/ip_ipsec.h>
66 #include <netipsec/ipsec.h>
67 #endif /* IPSEC*/
68
69 #include <machine/in_cksum.h>
70
71 #include <security/mac/mac_framework.h>
72
73 #define print_ip(x, a, y) printf("%s %d.%d.%d.%d%s",\
74 x, (ntohl(a.s_addr)>>24)&0xFF,\
75 (ntohl(a.s_addr)>>16)&0xFF,\
76 (ntohl(a.s_addr)>>8)&0xFF,\
77 (ntohl(a.s_addr))&0xFF, y);
78
79 u_short ip_id;
80
81 #ifdef MBUF_STRESS_TEST
82 int mbuf_frag_size = 0;
83 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW,
84 &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size");
85 #endif
86
87 static void ip_mloopback
88 (struct ifnet *, struct mbuf *, struct sockaddr_in *, int);
89
90
91 extern struct protosw inetsw[];
92
93 /*
94 * IP output. The packet in mbuf chain m contains a skeletal IP
95 * header (with len, off, ttl, proto, tos, src, dst).
96 * The mbuf chain containing the packet will be freed.
97 * The mbuf opt, if present, will not be freed.
98 * In the IP forwarding case, the packet will arrive with options already
99 * inserted, so must have a NULL opt pointer.
100 */
101 int
102 ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags,
103 struct ip_moptions *imo, struct inpcb *inp)
104 {
105 struct ip *ip;
106 struct ifnet *ifp = NULL; /* keep compiler happy */
107 struct mbuf *m0;
108 int hlen = sizeof (struct ip);
109 int mtu;
110 int len, error = 0;
111 struct sockaddr_in *dst = NULL; /* keep compiler happy */
112 struct in_ifaddr *ia = NULL;
113 int isbroadcast, sw_csum;
114 struct route iproute;
115 struct in_addr odst;
116 #ifdef IPFIREWALL_FORWARD
117 struct m_tag *fwd_tag = NULL;
118 #endif
119 M_ASSERTPKTHDR(m);
120
121 if (ro == NULL) {
122 ro = &iproute;
123 bzero(ro, sizeof (*ro));
124 }
125
126 if (inp != NULL)
127 INP_LOCK_ASSERT(inp);
128
129 if (opt) {
130 len = 0;
131 m = ip_insertoptions(m, opt, &len);
132 if (len != 0)
133 hlen = len;
134 }
135 ip = mtod(m, struct ip *);
136
137 /*
138 * Fill in IP header. If we are not allowing fragmentation,
139 * then the ip_id field is meaningless, but we don't set it
140 * to zero. Doing so causes various problems when devices along
141 * the path (routers, load balancers, firewalls, etc.) illegally
142 * disable DF on our packet. Note that a 16-bit counter
143 * will wrap around in less than 10 seconds at 100 Mbit/s on a
144 * medium with MTU 1500. See Steven M. Bellovin, "A Technique
145 * for Counting NATted Hosts", Proc. IMW'02, available at
146 * <http://www.cs.columbia.edu/~smb/papers/fnat.pdf>.
147 */
148 if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
149 ip->ip_v = IPVERSION;
150 ip->ip_hl = hlen >> 2;
151 ip->ip_id = ip_newid();
152 ipstat.ips_localout++;
153 } else {
154 hlen = ip->ip_hl << 2;
155 }
156
157 dst = (struct sockaddr_in *)&ro->ro_dst;
158 again:
159 /*
160 * If there is a cached route,
161 * check that it is to the same destination
162 * and is still up. If not, free it and try again.
163 * The address family should also be checked in case of sharing the
164 * cache with IPv6.
165 */
166 if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 ||
167 dst->sin_family != AF_INET ||
168 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) {
169 RTFREE(ro->ro_rt);
170 ro->ro_rt = (struct rtentry *)NULL;
171 }
172 #ifdef IPFIREWALL_FORWARD
173 if (ro->ro_rt == NULL && fwd_tag == NULL) {
174 #else
175 if (ro->ro_rt == NULL) {
176 #endif
177 bzero(dst, sizeof(*dst));
178 dst->sin_family = AF_INET;
179 dst->sin_len = sizeof(*dst);
180 dst->sin_addr = ip->ip_dst;
181 }
182 /*
183 * If routing to interface only, short circuit routing lookup.
184 * The use of an all-ones broadcast address implies this; an
185 * interface is specified by the broadcast address of an interface,
186 * or the destination address of a ptp interface.
187 */
188 if (flags & IP_SENDONES) {
189 if ((ia = ifatoia(ifa_ifwithbroadaddr(sintosa(dst)))) == NULL &&
190 (ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL) {
191 ipstat.ips_noroute++;
192 error = ENETUNREACH;
193 goto bad;
194 }
195 ip->ip_dst.s_addr = INADDR_BROADCAST;
196 dst->sin_addr = ip->ip_dst;
197 ifp = ia->ia_ifp;
198 ip->ip_ttl = 1;
199 isbroadcast = 1;
200 } else if (flags & IP_ROUTETOIF) {
201 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL &&
202 (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == NULL) {
203 ipstat.ips_noroute++;
204 error = ENETUNREACH;
205 goto bad;
206 }
207 ifp = ia->ia_ifp;
208 ip->ip_ttl = 1;
209 isbroadcast = in_broadcast(dst->sin_addr, ifp);
210 } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
211 imo != NULL && imo->imo_multicast_ifp != NULL) {
212 /*
213 * Bypass the normal routing lookup for multicast
214 * packets if the interface is specified.
215 */
216 ifp = imo->imo_multicast_ifp;
217 IFP_TO_IA(ifp, ia);
218 isbroadcast = 0; /* fool gcc */
219 } else {
220 /*
221 * We want to do any cloning requested by the link layer,
222 * as this is probably required in all cases for correct
223 * operation (as it is for ARP).
224 */
225 if (ro->ro_rt == NULL)
226 rtalloc_ign(ro, 0);
227 if (ro->ro_rt == NULL) {
228 ipstat.ips_noroute++;
229 error = EHOSTUNREACH;
230 goto bad;
231 }
232 ia = ifatoia(ro->ro_rt->rt_ifa);
233 ifp = ro->ro_rt->rt_ifp;
234 ro->ro_rt->rt_rmx.rmx_pksent++;
235 if (ro->ro_rt->rt_flags & RTF_GATEWAY)
236 dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
237 if (ro->ro_rt->rt_flags & RTF_HOST)
238 isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
239 else
240 isbroadcast = in_broadcast(dst->sin_addr, ifp);
241 }
242 /*
243 * Calculate MTU. If we have a route that is up, use that,
244 * otherwise use the interface's MTU.
245 */
246 if (ro->ro_rt != NULL && (ro->ro_rt->rt_flags & (RTF_UP|RTF_HOST))) {
247 /*
248 * This case can happen if the user changed the MTU
249 * of an interface after enabling IP on it. Because
250 * most netifs don't keep track of routes pointing to
251 * them, there is no way for one to update all its
252 * routes when the MTU is changed.
253 */
254 if (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)
255 ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
256 mtu = ro->ro_rt->rt_rmx.rmx_mtu;
257 } else {
258 mtu = ifp->if_mtu;
259 }
260 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
261 struct in_multi *inm;
262
263 m->m_flags |= M_MCAST;
264 /*
265 * IP destination address is multicast. Make sure "dst"
266 * still points to the address in "ro". (It may have been
267 * changed to point to a gateway address, above.)
268 */
269 dst = (struct sockaddr_in *)&ro->ro_dst;
270 /*
271 * See if the caller provided any multicast options
272 */
273 if (imo != NULL) {
274 ip->ip_ttl = imo->imo_multicast_ttl;
275 if (imo->imo_multicast_vif != -1)
276 ip->ip_src.s_addr =
277 ip_mcast_src ?
278 ip_mcast_src(imo->imo_multicast_vif) :
279 INADDR_ANY;
280 } else
281 ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
282 /*
283 * Confirm that the outgoing interface supports multicast.
284 */
285 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
286 if ((ifp->if_flags & IFF_MULTICAST) == 0) {
287 ipstat.ips_noroute++;
288 error = ENETUNREACH;
289 goto bad;
290 }
291 }
292 /*
293 * If source address not specified yet, use address
294 * of outgoing interface.
295 */
296 if (ip->ip_src.s_addr == INADDR_ANY) {
297 /* Interface may have no addresses. */
298 if (ia != NULL)
299 ip->ip_src = IA_SIN(ia)->sin_addr;
300 }
301
302 IN_MULTI_LOCK();
303 IN_LOOKUP_MULTI(ip->ip_dst, ifp, inm);
304 if (inm != NULL &&
305 (imo == NULL || imo->imo_multicast_loop)) {
306 IN_MULTI_UNLOCK();
307 /*
308 * If we belong to the destination multicast group
309 * on the outgoing interface, and the caller did not
310 * forbid loopback, loop back a copy.
311 */
312 ip_mloopback(ifp, m, dst, hlen);
313 }
314 else {
315 IN_MULTI_UNLOCK();
316 /*
317 * If we are acting as a multicast router, perform
318 * multicast forwarding as if the packet had just
319 * arrived on the interface to which we are about
320 * to send. The multicast forwarding function
321 * recursively calls this function, using the
322 * IP_FORWARDING flag to prevent infinite recursion.
323 *
324 * Multicasts that are looped back by ip_mloopback(),
325 * above, will be forwarded by the ip_input() routine,
326 * if necessary.
327 */
328 if (ip_mrouter && (flags & IP_FORWARDING) == 0) {
329 /*
330 * If rsvp daemon is not running, do not
331 * set ip_moptions. This ensures that the packet
332 * is multicast and not just sent down one link
333 * as prescribed by rsvpd.
334 */
335 if (!rsvp_on)
336 imo = NULL;
337 if (ip_mforward &&
338 ip_mforward(ip, ifp, m, imo) != 0) {
339 m_freem(m);
340 goto done;
341 }
342 }
343 }
344
345 /*
346 * Multicasts with a time-to-live of zero may be looped-
347 * back, above, but must not be transmitted on a network.
348 * Also, multicasts addressed to the loopback interface
349 * are not sent -- the above call to ip_mloopback() will
350 * loop back a copy if this host actually belongs to the
351 * destination group on the loopback interface.
352 */
353 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
354 m_freem(m);
355 goto done;
356 }
357
358 goto sendit;
359 }
360
361 /*
362 * If the source address is not specified yet, use the address
363 * of the outoing interface.
364 */
365 if (ip->ip_src.s_addr == INADDR_ANY) {
366 /* Interface may have no addresses. */
367 if (ia != NULL) {
368 ip->ip_src = IA_SIN(ia)->sin_addr;
369 }
370 }
371
372 /*
373 * Verify that we have any chance at all of being able to queue the
374 * packet or packet fragments, unless ALTQ is enabled on the given
375 * interface in which case packetdrop should be done by queueing.
376 */
377 #ifdef ALTQ
378 if ((!ALTQ_IS_ENABLED(&ifp->if_snd)) &&
379 ((ifp->if_snd.ifq_len + ip->ip_len / mtu + 1) >=
380 ifp->if_snd.ifq_maxlen))
381 #else
382 if ((ifp->if_snd.ifq_len + ip->ip_len / mtu + 1) >=
383 ifp->if_snd.ifq_maxlen)
384 #endif /* ALTQ */
385 {
386 error = ENOBUFS;
387 ipstat.ips_odropped++;
388 ifp->if_snd.ifq_drops += (ip->ip_len / ifp->if_mtu + 1);
389 goto bad;
390 }
391
392 /*
393 * Look for broadcast address and
394 * verify user is allowed to send
395 * such a packet.
396 */
397 if (isbroadcast) {
398 if ((ifp->if_flags & IFF_BROADCAST) == 0) {
399 error = EADDRNOTAVAIL;
400 goto bad;
401 }
402 if ((flags & IP_ALLOWBROADCAST) == 0) {
403 error = EACCES;
404 goto bad;
405 }
406 /* don't allow broadcast messages to be fragmented */
407 if (ip->ip_len > mtu) {
408 error = EMSGSIZE;
409 goto bad;
410 }
411 m->m_flags |= M_BCAST;
412 } else {
413 m->m_flags &= ~M_BCAST;
414 }
415
416 sendit:
417 #ifdef IPSEC
418 switch(ip_ipsec_output(&m, inp, &flags, &error, &ro, &iproute, &dst, &ia, &ifp)) {
419 case 1:
420 goto bad;
421 case -1:
422 goto done;
423 case 0:
424 default:
425 break; /* Continue with packet processing. */
426 }
427 /* Update variables that are affected by ipsec4_output(). */
428 ip = mtod(m, struct ip *);
429 hlen = ip->ip_hl << 2;
430 #endif /* IPSEC */
431
432 /* Jump over all PFIL processing if hooks are not active. */
433 if (!PFIL_HOOKED(&inet_pfil_hook))
434 goto passout;
435
436 /* Run through list of hooks for output packets. */
437 odst.s_addr = ip->ip_dst.s_addr;
438 error = pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT, inp);
439 if (error != 0 || m == NULL)
440 goto done;
441
442 ip = mtod(m, struct ip *);
443
444 /* See if destination IP address was changed by packet filter. */
445 if (odst.s_addr != ip->ip_dst.s_addr) {
446 m->m_flags |= M_SKIP_FIREWALL;
447 /* If destination is now ourself drop to ip_input(). */
448 if (in_localip(ip->ip_dst)) {
449 m->m_flags |= M_FASTFWD_OURS;
450 if (m->m_pkthdr.rcvif == NULL)
451 m->m_pkthdr.rcvif = loif;
452 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
453 m->m_pkthdr.csum_flags |=
454 CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
455 m->m_pkthdr.csum_data = 0xffff;
456 }
457 m->m_pkthdr.csum_flags |=
458 CSUM_IP_CHECKED | CSUM_IP_VALID;
459
460 error = netisr_queue(NETISR_IP, m);
461 goto done;
462 } else
463 goto again; /* Redo the routing table lookup. */
464 }
465
466 #ifdef IPFIREWALL_FORWARD
467 /* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */
468 if (m->m_flags & M_FASTFWD_OURS) {
469 if (m->m_pkthdr.rcvif == NULL)
470 m->m_pkthdr.rcvif = loif;
471 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
472 m->m_pkthdr.csum_flags |=
473 CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
474 m->m_pkthdr.csum_data = 0xffff;
475 }
476 m->m_pkthdr.csum_flags |=
477 CSUM_IP_CHECKED | CSUM_IP_VALID;
478
479 error = netisr_queue(NETISR_IP, m);
480 goto done;
481 }
482 /* Or forward to some other address? */
483 fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
484 if (fwd_tag) {
485 dst = (struct sockaddr_in *)&ro->ro_dst;
486 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in));
487 m->m_flags |= M_SKIP_FIREWALL;
488 m_tag_delete(m, fwd_tag);
489 goto again;
490 }
491 #endif /* IPFIREWALL_FORWARD */
492
493 passout:
494 /* 127/8 must not appear on wire - RFC1122. */
495 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
496 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
497 if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
498 ipstat.ips_badaddr++;
499 error = EADDRNOTAVAIL;
500 goto bad;
501 }
502 }
503
504 m->m_pkthdr.csum_flags |= CSUM_IP;
505 sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist;
506 if (sw_csum & CSUM_DELAY_DATA) {
507 in_delayed_cksum(m);
508 sw_csum &= ~CSUM_DELAY_DATA;
509 }
510 m->m_pkthdr.csum_flags &= ifp->if_hwassist;
511
512 /*
513 * If small enough for interface, or the interface will take
514 * care of the fragmentation for us, we can just send directly.
515 */
516 if (ip->ip_len <= mtu ||
517 (m->m_pkthdr.csum_flags & ifp->if_hwassist & CSUM_TSO) != 0 ||
518 ((ip->ip_off & IP_DF) == 0 && (ifp->if_hwassist & CSUM_FRAGMENT))) {
519 ip->ip_len = htons(ip->ip_len);
520 ip->ip_off = htons(ip->ip_off);
521 ip->ip_sum = 0;
522 if (sw_csum & CSUM_DELAY_IP)
523 ip->ip_sum = in_cksum(m, hlen);
524
525 /*
526 * Record statistics for this interface address.
527 * With CSUM_TSO the byte/packet count will be slightly
528 * incorrect because we count the IP+TCP headers only
529 * once instead of for every generated packet.
530 */
531 if (!(flags & IP_FORWARDING) && ia) {
532 if (m->m_pkthdr.csum_flags & CSUM_TSO)
533 ia->ia_ifa.if_opackets +=
534 m->m_pkthdr.len / m->m_pkthdr.tso_segsz;
535 else
536 ia->ia_ifa.if_opackets++;
537 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
538 }
539 #ifdef MBUF_STRESS_TEST
540 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size)
541 m = m_fragment(m, M_DONTWAIT, mbuf_frag_size);
542 #endif
543 /*
544 * Reset layer specific mbuf flags
545 * to avoid confusing lower layers.
546 */
547 m->m_flags &= ~(M_PROTOFLAGS);
548
549 error = (*ifp->if_output)(ifp, m,
550 (struct sockaddr *)dst, ro->ro_rt);
551 goto done;
552 }
553
554 /* Balk when DF bit is set or the interface didn't support TSO. */
555 if ((ip->ip_off & IP_DF) || (m->m_pkthdr.csum_flags & CSUM_TSO)) {
556 error = EMSGSIZE;
557 ipstat.ips_cantfrag++;
558 goto bad;
559 }
560
561 /*
562 * Too large for interface; fragment if possible. If successful,
563 * on return, m will point to a list of packets to be sent.
564 */
565 error = ip_fragment(ip, &m, mtu, ifp->if_hwassist, sw_csum);
566 if (error)
567 goto bad;
568 for (; m; m = m0) {
569 m0 = m->m_nextpkt;
570 m->m_nextpkt = 0;
571 if (error == 0) {
572 /* Record statistics for this interface address. */
573 if (ia != NULL) {
574 ia->ia_ifa.if_opackets++;
575 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
576 }
577 /*
578 * Reset layer specific mbuf flags
579 * to avoid confusing upper layers.
580 */
581 m->m_flags &= ~(M_PROTOFLAGS);
582
583 error = (*ifp->if_output)(ifp, m,
584 (struct sockaddr *)dst, ro->ro_rt);
585 } else
586 m_freem(m);
587 }
588
589 if (error == 0)
590 ipstat.ips_fragmented++;
591
592 done:
593 if (ro == &iproute && ro->ro_rt) {
594 RTFREE(ro->ro_rt);
595 }
596 return (error);
597 bad:
598 m_freem(m);
599 goto done;
600 }
601
602 /*
603 * Create a chain of fragments which fit the given mtu. m_frag points to the
604 * mbuf to be fragmented; on return it points to the chain with the fragments.
605 * Return 0 if no error. If error, m_frag may contain a partially built
606 * chain of fragments that should be freed by the caller.
607 *
608 * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
609 * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP).
610 */
611 int
612 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
613 u_long if_hwassist_flags, int sw_csum)
614 {
615 int error = 0;
616 int hlen = ip->ip_hl << 2;
617 int len = (mtu - hlen) & ~7; /* size of payload in each fragment */
618 int off;
619 struct mbuf *m0 = *m_frag; /* the original packet */
620 int firstlen;
621 struct mbuf **mnext;
622 int nfrags;
623
624 if (ip->ip_off & IP_DF) { /* Fragmentation not allowed */
625 ipstat.ips_cantfrag++;
626 return EMSGSIZE;
627 }
628
629 /*
630 * Must be able to put at least 8 bytes per fragment.
631 */
632 if (len < 8)
633 return EMSGSIZE;
634
635 /*
636 * If the interface will not calculate checksums on
637 * fragmented packets, then do it here.
638 */
639 if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA &&
640 (if_hwassist_flags & CSUM_IP_FRAGS) == 0) {
641 in_delayed_cksum(m0);
642 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
643 }
644
645 if (len > PAGE_SIZE) {
646 /*
647 * Fragment large datagrams such that each segment
648 * contains a multiple of PAGE_SIZE amount of data,
649 * plus headers. This enables a receiver to perform
650 * page-flipping zero-copy optimizations.
651 *
652 * XXX When does this help given that sender and receiver
653 * could have different page sizes, and also mtu could
654 * be less than the receiver's page size ?
655 */
656 int newlen;
657 struct mbuf *m;
658
659 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next)
660 off += m->m_len;
661
662 /*
663 * firstlen (off - hlen) must be aligned on an
664 * 8-byte boundary
665 */
666 if (off < hlen)
667 goto smart_frag_failure;
668 off = ((off - hlen) & ~7) + hlen;
669 newlen = (~PAGE_MASK) & mtu;
670 if ((newlen + sizeof (struct ip)) > mtu) {
671 /* we failed, go back the default */
672 smart_frag_failure:
673 newlen = len;
674 off = hlen + len;
675 }
676 len = newlen;
677
678 } else {
679 off = hlen + len;
680 }
681
682 firstlen = off - hlen;
683 mnext = &m0->m_nextpkt; /* pointer to next packet */
684
685 /*
686 * Loop through length of segment after first fragment,
687 * make new header and copy data of each part and link onto chain.
688 * Here, m0 is the original packet, m is the fragment being created.
689 * The fragments are linked off the m_nextpkt of the original
690 * packet, which after processing serves as the first fragment.
691 */
692 for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) {
693 struct ip *mhip; /* ip header on the fragment */
694 struct mbuf *m;
695 int mhlen = sizeof (struct ip);
696
697 MGETHDR(m, M_DONTWAIT, MT_DATA);
698 if (m == NULL) {
699 error = ENOBUFS;
700 ipstat.ips_odropped++;
701 goto done;
702 }
703 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
704 /*
705 * In the first mbuf, leave room for the link header, then
706 * copy the original IP header including options. The payload
707 * goes into an additional mbuf chain returned by m_copy().
708 */
709 m->m_data += max_linkhdr;
710 mhip = mtod(m, struct ip *);
711 *mhip = *ip;
712 if (hlen > sizeof (struct ip)) {
713 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
714 mhip->ip_v = IPVERSION;
715 mhip->ip_hl = mhlen >> 2;
716 }
717 m->m_len = mhlen;
718 /* XXX do we need to add ip->ip_off below ? */
719 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off;
720 if (off + len >= ip->ip_len) { /* last fragment */
721 len = ip->ip_len - off;
722 m->m_flags |= M_LASTFRAG;
723 } else
724 mhip->ip_off |= IP_MF;
725 mhip->ip_len = htons((u_short)(len + mhlen));
726 m->m_next = m_copy(m0, off, len);
727 if (m->m_next == NULL) { /* copy failed */
728 m_free(m);
729 error = ENOBUFS; /* ??? */
730 ipstat.ips_odropped++;
731 goto done;
732 }
733 m->m_pkthdr.len = mhlen + len;
734 m->m_pkthdr.rcvif = NULL;
735 #ifdef MAC
736 mac_create_fragment(m0, m);
737 #endif
738 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
739 mhip->ip_off = htons(mhip->ip_off);
740 mhip->ip_sum = 0;
741 if (sw_csum & CSUM_DELAY_IP)
742 mhip->ip_sum = in_cksum(m, mhlen);
743 *mnext = m;
744 mnext = &m->m_nextpkt;
745 }
746 ipstat.ips_ofragments += nfrags;
747
748 /* set first marker for fragment chain */
749 m0->m_flags |= M_FIRSTFRAG | M_FRAG;
750 m0->m_pkthdr.csum_data = nfrags;
751
752 /*
753 * Update first fragment by trimming what's been copied out
754 * and updating header.
755 */
756 m_adj(m0, hlen + firstlen - ip->ip_len);
757 m0->m_pkthdr.len = hlen + firstlen;
758 ip->ip_len = htons((u_short)m0->m_pkthdr.len);
759 ip->ip_off |= IP_MF;
760 ip->ip_off = htons(ip->ip_off);
761 ip->ip_sum = 0;
762 if (sw_csum & CSUM_DELAY_IP)
763 ip->ip_sum = in_cksum(m0, hlen);
764
765 done:
766 *m_frag = m0;
767 return error;
768 }
769
770 void
771 in_delayed_cksum(struct mbuf *m)
772 {
773 struct ip *ip;
774 u_short csum, offset;
775
776 ip = mtod(m, struct ip *);
777 offset = ip->ip_hl << 2 ;
778 csum = in_cksum_skip(m, ip->ip_len, offset);
779 if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
780 csum = 0xffff;
781 offset += m->m_pkthdr.csum_data; /* checksum offset */
782
783 if (offset + sizeof(u_short) > m->m_len) {
784 printf("delayed m_pullup, m->len: %d off: %d p: %d\n",
785 m->m_len, offset, ip->ip_p);
786 /*
787 * XXX
788 * this shouldn't happen, but if it does, the
789 * correct behavior may be to insert the checksum
790 * in the appropriate next mbuf in the chain.
791 */
792 return;
793 }
794 *(u_short *)(m->m_data + offset) = csum;
795 }
796
797 /*
798 * IP socket option processing.
799 */
800 int
801 ip_ctloutput(struct socket *so, struct sockopt *sopt)
802 {
803 struct inpcb *inp = sotoinpcb(so);
804 int error, optval;
805
806 error = optval = 0;
807 if (sopt->sopt_level != IPPROTO_IP) {
808 return (EINVAL);
809 }
810
811 switch (sopt->sopt_dir) {
812 case SOPT_SET:
813 switch (sopt->sopt_name) {
814 case IP_OPTIONS:
815 #ifdef notyet
816 case IP_RETOPTS:
817 #endif
818 {
819 struct mbuf *m;
820 if (sopt->sopt_valsize > MLEN) {
821 error = EMSGSIZE;
822 break;
823 }
824 MGET(m, sopt->sopt_td ? M_TRYWAIT : M_DONTWAIT, MT_DATA);
825 if (m == NULL) {
826 error = ENOBUFS;
827 break;
828 }
829 m->m_len = sopt->sopt_valsize;
830 error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
831 m->m_len);
832 if (error) {
833 m_free(m);
834 break;
835 }
836 INP_LOCK(inp);
837 error = ip_pcbopts(inp, sopt->sopt_name, m);
838 INP_UNLOCK(inp);
839 return (error);
840 }
841
842 case IP_TOS:
843 case IP_TTL:
844 case IP_MINTTL:
845 case IP_RECVOPTS:
846 case IP_RECVRETOPTS:
847 case IP_RECVDSTADDR:
848 case IP_RECVTTL:
849 case IP_RECVIF:
850 case IP_FAITH:
851 case IP_ONESBCAST:
852 case IP_DONTFRAG:
853 error = sooptcopyin(sopt, &optval, sizeof optval,
854 sizeof optval);
855 if (error)
856 break;
857
858 switch (sopt->sopt_name) {
859 case IP_TOS:
860 inp->inp_ip_tos = optval;
861 break;
862
863 case IP_TTL:
864 inp->inp_ip_ttl = optval;
865 break;
866
867 case IP_MINTTL:
868 if (optval > 0 && optval <= MAXTTL)
869 inp->inp_ip_minttl = optval;
870 else
871 error = EINVAL;
872 break;
873
874 #define OPTSET(bit) do { \
875 INP_LOCK(inp); \
876 if (optval) \
877 inp->inp_flags |= bit; \
878 else \
879 inp->inp_flags &= ~bit; \
880 INP_UNLOCK(inp); \
881 } while (0)
882
883 case IP_RECVOPTS:
884 OPTSET(INP_RECVOPTS);
885 break;
886
887 case IP_RECVRETOPTS:
888 OPTSET(INP_RECVRETOPTS);
889 break;
890
891 case IP_RECVDSTADDR:
892 OPTSET(INP_RECVDSTADDR);
893 break;
894
895 case IP_RECVTTL:
896 OPTSET(INP_RECVTTL);
897 break;
898
899 case IP_RECVIF:
900 OPTSET(INP_RECVIF);
901 break;
902
903 case IP_FAITH:
904 OPTSET(INP_FAITH);
905 break;
906
907 case IP_ONESBCAST:
908 OPTSET(INP_ONESBCAST);
909 break;
910 case IP_DONTFRAG:
911 OPTSET(INP_DONTFRAG);
912 break;
913 }
914 break;
915 #undef OPTSET
916
917 /*
918 * Multicast socket options are processed by the in_mcast
919 * module.
920 */
921 case IP_MULTICAST_IF:
922 case IP_MULTICAST_VIF:
923 case IP_MULTICAST_TTL:
924 case IP_MULTICAST_LOOP:
925 case IP_ADD_MEMBERSHIP:
926 case IP_DROP_MEMBERSHIP:
927 case IP_ADD_SOURCE_MEMBERSHIP:
928 case IP_DROP_SOURCE_MEMBERSHIP:
929 case IP_BLOCK_SOURCE:
930 case IP_UNBLOCK_SOURCE:
931 case IP_MSFILTER:
932 case MCAST_JOIN_GROUP:
933 case MCAST_LEAVE_GROUP:
934 case MCAST_JOIN_SOURCE_GROUP:
935 case MCAST_LEAVE_SOURCE_GROUP:
936 case MCAST_BLOCK_SOURCE:
937 case MCAST_UNBLOCK_SOURCE:
938 error = inp_setmoptions(inp, sopt);
939 break;
940
941 case IP_PORTRANGE:
942 error = sooptcopyin(sopt, &optval, sizeof optval,
943 sizeof optval);
944 if (error)
945 break;
946
947 INP_LOCK(inp);
948 switch (optval) {
949 case IP_PORTRANGE_DEFAULT:
950 inp->inp_flags &= ~(INP_LOWPORT);
951 inp->inp_flags &= ~(INP_HIGHPORT);
952 break;
953
954 case IP_PORTRANGE_HIGH:
955 inp->inp_flags &= ~(INP_LOWPORT);
956 inp->inp_flags |= INP_HIGHPORT;
957 break;
958
959 case IP_PORTRANGE_LOW:
960 inp->inp_flags &= ~(INP_HIGHPORT);
961 inp->inp_flags |= INP_LOWPORT;
962 break;
963
964 default:
965 error = EINVAL;
966 break;
967 }
968 INP_UNLOCK(inp);
969 break;
970
971 #ifdef IPSEC
972 case IP_IPSEC_POLICY:
973 {
974 caddr_t req;
975 size_t len = 0;
976 int priv;
977 struct mbuf *m;
978 int optname;
979
980 if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
981 break;
982 if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
983 break;
984 if (sopt->sopt_td != NULL) {
985 /*
986 * XXXRW: Would be more desirable to do this
987 * one layer down so that we only exercise
988 * privilege if it is needed.
989 */
990 error = priv_check(sopt->sopt_td,
991 PRIV_NETINET_IPSEC);
992 if (error)
993 priv = 0;
994 else
995 priv = 1;
996 } else
997 priv = 1;
998 req = mtod(m, caddr_t);
999 len = m->m_len;
1000 optname = sopt->sopt_name;
1001 error = ipsec4_set_policy(inp, optname, req, len, priv);
1002 m_freem(m);
1003 break;
1004 }
1005 #endif /* IPSEC */
1006
1007 default:
1008 error = ENOPROTOOPT;
1009 break;
1010 }
1011 break;
1012
1013 case SOPT_GET:
1014 switch (sopt->sopt_name) {
1015 case IP_OPTIONS:
1016 case IP_RETOPTS:
1017 if (inp->inp_options)
1018 error = sooptcopyout(sopt,
1019 mtod(inp->inp_options,
1020 char *),
1021 inp->inp_options->m_len);
1022 else
1023 sopt->sopt_valsize = 0;
1024 break;
1025
1026 case IP_TOS:
1027 case IP_TTL:
1028 case IP_MINTTL:
1029 case IP_RECVOPTS:
1030 case IP_RECVRETOPTS:
1031 case IP_RECVDSTADDR:
1032 case IP_RECVTTL:
1033 case IP_RECVIF:
1034 case IP_PORTRANGE:
1035 case IP_FAITH:
1036 case IP_ONESBCAST:
1037 case IP_DONTFRAG:
1038 switch (sopt->sopt_name) {
1039
1040 case IP_TOS:
1041 optval = inp->inp_ip_tos;
1042 break;
1043
1044 case IP_TTL:
1045 optval = inp->inp_ip_ttl;
1046 break;
1047
1048 case IP_MINTTL:
1049 optval = inp->inp_ip_minttl;
1050 break;
1051
1052 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0)
1053
1054 case IP_RECVOPTS:
1055 optval = OPTBIT(INP_RECVOPTS);
1056 break;
1057
1058 case IP_RECVRETOPTS:
1059 optval = OPTBIT(INP_RECVRETOPTS);
1060 break;
1061
1062 case IP_RECVDSTADDR:
1063 optval = OPTBIT(INP_RECVDSTADDR);
1064 break;
1065
1066 case IP_RECVTTL:
1067 optval = OPTBIT(INP_RECVTTL);
1068 break;
1069
1070 case IP_RECVIF:
1071 optval = OPTBIT(INP_RECVIF);
1072 break;
1073
1074 case IP_PORTRANGE:
1075 if (inp->inp_flags & INP_HIGHPORT)
1076 optval = IP_PORTRANGE_HIGH;
1077 else if (inp->inp_flags & INP_LOWPORT)
1078 optval = IP_PORTRANGE_LOW;
1079 else
1080 optval = 0;
1081 break;
1082
1083 case IP_FAITH:
1084 optval = OPTBIT(INP_FAITH);
1085 break;
1086
1087 case IP_ONESBCAST:
1088 optval = OPTBIT(INP_ONESBCAST);
1089 break;
1090 case IP_DONTFRAG:
1091 optval = OPTBIT(INP_DONTFRAG);
1092 break;
1093 }
1094 error = sooptcopyout(sopt, &optval, sizeof optval);
1095 break;
1096
1097 /*
1098 * Multicast socket options are processed by the in_mcast
1099 * module.
1100 */
1101 case IP_MULTICAST_IF:
1102 case IP_MULTICAST_VIF:
1103 case IP_MULTICAST_TTL:
1104 case IP_MULTICAST_LOOP:
1105 case IP_MSFILTER:
1106 error = inp_getmoptions(inp, sopt);
1107 break;
1108
1109 #ifdef IPSEC
1110 case IP_IPSEC_POLICY:
1111 {
1112 struct mbuf *m = NULL;
1113 caddr_t req = NULL;
1114 size_t len = 0;
1115
1116 if (m != 0) {
1117 req = mtod(m, caddr_t);
1118 len = m->m_len;
1119 }
1120 error = ipsec4_get_policy(sotoinpcb(so), req, len, &m);
1121 if (error == 0)
1122 error = soopt_mcopyout(sopt, m); /* XXX */
1123 if (error == 0)
1124 m_freem(m);
1125 break;
1126 }
1127 #endif /* IPSEC */
1128
1129 default:
1130 error = ENOPROTOOPT;
1131 break;
1132 }
1133 break;
1134 }
1135 return (error);
1136 }
1137
1138 /*
1139 * Routine called from ip_output() to loop back a copy of an IP multicast
1140 * packet to the input queue of a specified interface. Note that this
1141 * calls the output routine of the loopback "driver", but with an interface
1142 * pointer that might NOT be a loopback interface -- evil, but easier than
1143 * replicating that code here.
1144 */
1145 static void
1146 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst,
1147 int hlen)
1148 {
1149 register struct ip *ip;
1150 struct mbuf *copym;
1151
1152 copym = m_copy(m, 0, M_COPYALL);
1153 if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
1154 copym = m_pullup(copym, hlen);
1155 if (copym != NULL) {
1156 /* If needed, compute the checksum and mark it as valid. */
1157 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
1158 in_delayed_cksum(copym);
1159 copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
1160 copym->m_pkthdr.csum_flags |=
1161 CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
1162 copym->m_pkthdr.csum_data = 0xffff;
1163 }
1164 /*
1165 * We don't bother to fragment if the IP length is greater
1166 * than the interface's MTU. Can this possibly matter?
1167 */
1168 ip = mtod(copym, struct ip *);
1169 ip->ip_len = htons(ip->ip_len);
1170 ip->ip_off = htons(ip->ip_off);
1171 ip->ip_sum = 0;
1172 ip->ip_sum = in_cksum(copym, hlen);
1173 /*
1174 * NB:
1175 * It's not clear whether there are any lingering
1176 * reentrancy problems in other areas which might
1177 * be exposed by using ip_input directly (in
1178 * particular, everything which modifies the packet
1179 * in-place). Yet another option is using the
1180 * protosw directly to deliver the looped back
1181 * packet. For the moment, we'll err on the side
1182 * of safety by using if_simloop().
1183 */
1184 #if 1 /* XXX */
1185 if (dst->sin_family != AF_INET) {
1186 printf("ip_mloopback: bad address family %d\n",
1187 dst->sin_family);
1188 dst->sin_family = AF_INET;
1189 }
1190 #endif
1191
1192 #ifdef notdef
1193 copym->m_pkthdr.rcvif = ifp;
1194 ip_input(copym);
1195 #else
1196 if_simloop(ifp, copym, dst->sin_family, 0);
1197 #endif
1198 }
1199 }
Cache object: 13e25874fedccae3f9fbcc7368b3ccd4
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